Using Retrofit and GreenDao with nested json objects
I want to combine Retrofit and GreenDao, but I have a problem with nested Json-Objects. My nested fields are left blank.
This is Json DataStructure
[
{
"id": 1,
"street": "Streetname",
"zipcode": 12345,
"city": "MyCity",
"phone_number": "+123456789",
"position": "12.0000, 9.0000",
"company": {
"title": "CompanyName",
"group": {
"title": "GroupName"
}
}
}
]
My DaoGenerator looks like this
Entity customItem = schema.addEntity("CustomItems");
customItem.addIdProperty();
customItem.addStringProperty("street");
customItem.addIntProperty("zipcode");
customItem.addStringProperty("city");
customItem.addStringProperty("phone_number");
customItem.addStringProperty("position");
Entity company = schema.addEntity("Company");
company.addIdProperty();
company.addStringProperty("title");
Entity group = schema.addEntity("Group");
group.addIdProperty();
group.addStringProperty("title");
Property companyPropId = customItem.addLongProperty("companyId").notNull().getProperty();
customItem.addToOne(company, companyPropId);
Property groupPropId = company.addLongProperty("groupId").notNull().getProperty();
company.addToOne(group, groupPropId);
My problem is customItem.getCompany () returns null, but the "id" values in "position" are accurate. I'm not sure what the problem is, as my CustomItem class contains a member
private Company company;
and an installer for the company and I don't see any typo.
public void setCompany(Company company) {
if (company == null) {
throw new DaoException("To-one property 'companyId' has not-null constraint; cannot set to-one to null");
}
synchronized (this) {
this.company = company;
companyId = company.getId();
company__resolvedKey = companyId;
}
}
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I ran it, but I had several problems.
1) When I wanted to save CustomItem, Company and Group I, there was a problem with getters getCompany () and getGroup () returning null, because they do not return the item directly, but retrieve it from the DB. So I added a recipient to the generated CustomItem object class that just returns a company member. Now I was able to insert the company into the db. Getter looks like this:
// KEEP METHODS - put your custom methods here
public Company getCompanyLocal() {
return company;
}
// KEEP METHODS END
The same work for the Company and the Group. But there was another problem ...
2) The second problem was that the group "Group" as "group" is a reserved SQL keyword. I see one solution and bad solution to this problem:
-
The good thing is to change your json data from "group" to ie "business_group" and change your DAOs accordingly. Done.
-
Bad workaround, if you are in the same situation as me where you cannot change the json you can do the following. I don't save the group at all, but I can access it through the company. It appears there somehow. So I added a getter to my company class, for example the CustomItem getter. It works, but you should avoid it. As you cannot query your DB for group or load group from db.
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To solve your second problem, add this code to your DAO generator:
beacon.addStringProperty("business_group"); //Daogenerator
And add this code to your network manager:
//add this into your network manager
FieldNamingStrategy strategy = new FieldNamingStrategy() {
@Override
public String translateName(Field field) {
if(field.getName().equalsIgnoreCase("business_group")) {
return "group";
} else {
return field.getName();
}
}
};
And set this property for your Gson:
//add this in your Gson
.setFieldNamingStrategy(strategy)
hope this helps!
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